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What&#8217;s that noise?

Today’s disc brake systems commonly make some minor noise during normal operation such as whirring and occasionally squeaking. Most of these noises are considered normal. However, what about noises that aren&#8217;t considered ‘normal’ such as grinding or scraping?

First we have to determine if the grinding noise is during driving, during brake application, or both. In this article we want to focus on some of the causes of grinding noises during driving when the brakes aren&#8217;t being applied, as opposed to grinding when applying the brakes. We’ll save that for another article.

Debris
While its rare, this can be the most perplexing of all brake noise issues: Debris caught in the system. Sometimes a small rock, road salt, or other debris can find its way into the braking system or hub area. When this happens, it can get wedged in between the hub or heat shield and the rotor, causing a constant grinding or rubbing noise during driving. Sometimes this can be resolved by rolling the car backwards while applying the brake a few times. This motion can dislodge problematic intruder with little effort. But in the case that this doesn&#8217;t fix the issue, the system may have to be disassembled to resolve the problem.

Surface contamination
When there is a significant amount of corrosion or rust build up on the rotor faces from the vehicle being stored for an extended time, or highly corrosive wheel cleaners, there can be a period where the brakes will make a rubbing noise until the pads can properly clean the surfaces. This issue usually resolves itself by driving cautiously until the braking surfaces are free of contamination. It is strongly recommended that additional braking distances are used during this period for safety. If this doesn&#8217;t resolve itself fairly quickly, then there may be a larger issue at hand.

Damaged components
The spacing between some of the braking components can be very small, so the slightest variation in the alignment of parts can cause problems where parts can make contact with each other. For example, in heavy snow areas when there is a lot of ice and snow that can build up in the wheels, metal heat shields can be damaged or deformed and cause them to come in contact with the rotor or hub. This can also happen in off-road or gravel driving environments. The only way to resolve this is to disassemble the components and either replace, or repair the component that is bent or damaged.

Caliper or pad issues
Grinding noises can be caused by a few different pad or caliper problems. First would be a caliper that is seized or stuck. This can be caused by corrosion or simply due to wear and tear. If a caliper is seized, when the pedal is released, the pad doesn&#8217;t pull away from the rotor as it should and can stay in contact with the rotor during driving. Additionally, brake pads that are designed to move freely in the caliper can become seized or can sometimes become dislodged allowing unintended movement causing the pad to come in contact with the rotor when it isn&#8217;t supposed to, also resulting in grinding noises. Re-seating the pads with appropriate grease can usually remedy this problem.

Parking brake
The parking brake system can cause grinding issues two different ways. First, and most common is that the parking brake either wasn&#8217;t released, or wasn&#8217;t released completely. This is the first thing to check when any grinding noises occur, its quick and easy to try again to release the brake to resolve the problem. Secondly, the because the parking brake system isn&#8217;t used as often as the primary braking system, the parking brake can be subject to seizing or sticking more often than you might expect. The best bet is to try applying the parking brake and releasing it again in hopes of breaking it loose. If that doesn&#8217;t work, a more comprehensive examination may be required.

Generally, these issues we’ve reviewed aren&#8217;t cause for alarm, as many of them can be fixed quickly and easily. However, if you are experiencing problems other than these mentioned, or that cant be quickly resolved, DBA USA strongly suggests you have your vehicle checked out thoroughly by a professional. Because the braking system is the most important safety feature of your vehicle.